Which combination of factors is most suitable for increasing the electrical conductivity of metals? more valence electrons and larger atomic radius fewer valence electrons and larger atomic radius more valence electrons and smaller atomic radius O fewer valence electrons and smaller atomic radius

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains

What is the independent variable in this investigation? mass volume sample number substance density

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.